Bicycles have long been a common mode of human-powered transportation. Modern bicycles employ precision manufactured components, including pedal cranks, chains and drive sprockets, so that a high proportion of the energy applied to the pedals by the rider is transmitted to the rear drive wheel. Also, through the use of higher strength materials, modern bicycles are also much lighter in weight than in the past making them easier to pedal.
Nonetheless, bicycles do suffer from substantial drawbacks. For instance, because of the upright position of the bicycle rider, at higher speeds, i.e., over 25 m.p.h., a very high proportion of the effort expended by the rider is used to overcome wind resistance. Also, because the rider sits relatively high off the ground, hard braking can lead to severe skidding of the tires.
The foregoing drawbacks of conventional bicycles are overcome in recumbent cycles wherein the rider sits behind the foot pedals in a recumbent or reclining position in a seat which usually is provided with a backrest. Unlike in a bicycle in which the rider's legs extend downwardly in a generally vertical direction, in a recumbent cycle the rider's legs extend forwardly substantially parallel to the ground. As such the combined frontal area of a recumbent cycle and rider is typically substantially less than in a conventional bicycle, thus resulting in reduced wind resistance.
Also, because of the feet-forward riding position and the low center of gravity of the rider and vehicle, recumbent vehicles are typically safer than conventional bicycles. The rider can use his legs to brace himself during a collision to stay seated to avoid sliding or being pitched forward. In addition, the low center of gravity reduces the skidding of the wheels of the recumbent vehicle during hard braking. Further, the seat of a recumbent cycle typically supports more of the rider's body area, including his back, so that the weight of the rider is distributed over a larger surface for greater comfort. In a recumbent position the rider is able to apply greater thrust power to the pedals since his back and hips are braced by the seat. Moreover, during pedaling, the loads applied by the rider's body against the seat in reaction to the forces applied to the foot pedals by the rider's legs are transmitted to the seat through the hips and shoulders of the rider. This enables the upper torso and arms of the rider to remain relaxed while full power is being applied to the foot pedals.
Various types of recumbent vehicles are known, including recumbent bicycles are exemplified by U.S. Pat. Nos. 4,283,070, 4,333,664 and 4,659,098. A drawback of recumbent bicycles is that although the rider may be positioned at a lower elevation than in a conventional bicycle, the rider generally sits above the level of the smaller wheel of the bicycle, which usually is a substantial distance above the ground. As such, the combined center of gravity of the rider and bicycle may not be significantly lower than in a conventional bicycle. A further disadvantage of a recumbent bicycle is that it is more difficult to balance than a regular bicycle because of the recumbent position of the rider. Another type of recumbent vehicle is the recumbent tricycle. The foregoing disadvantages of recumbent bicycles are not present in recumbent tricycles since the rider typically sits between the forward and rearward wheels on a lowered frame rather than above the wheels in the case of a recumbent bicycle. Also, because three wheels are used, the difficulty of balancing a recumbent bicycle does not exist in a recumbent tricycle.
Recumbent tricycles have been constructed in various configurations. For instance, in one configuration the foot pedals are drivingly interconnected to one or two forward drive wheels with the steering accomplished through the rear wheel(s). Examples of such recumbent tricycles are disclosed in U.S. Pat. Nos. 3,960,392, 4,198,072 and 4,497,502. One disadvantage of steering the rear wheels of a recumbent tricycle is that the steering geometry, and thus the steering "effect", of the vehicle is different than that which riders are typically accustomed to from riding a bicycle or driving a car.
Other recumbent tricycle configurations including a "front drive - front steer" arrangement illustrated in U.S. Pat. No. 4,456,277 and a "rear drive - front and rear steer" configuration disclosed in U.S. Pat. No. 4,592,563. Both of these configurations are substantially more complicated than in recumbent tricycles in which the steering and driving functions of the vehicle are separated between the forward and rearward wheels.
In a further configuration, the front wheels of the recumbent tricycle are used for steering with the drive torque from the foot pedals being transmitted to the rear wheel. Examples of such recumbent tricycles are disclosed by U.S. Pat. Nos. 3,913,929 and 4,548,421.
Aspects of known recumbent tricycles that have not been significantly developed are the control systems used to steer the steerable wheels, actuate the vehicle's brakes and shift the multi-speed transmissions commonly employed in recumbent tricycles. Some recumbent tricycles merely employ a typical bicycle handlebar positioned either below the vehicle seat (see for instance aforementioned U.S. Pat. Nos. 4,198,072 and 4,456,277) or in front of the rider (see for instance aforementioned U.S. Pat. No. 4,548,421). Locating the handlebar below the seat makes the hand controls awkward and difficult to operate, whereas locating the handlebar in front of the rider can result in serious injuries if the rider accidentally slides or pitches forward into the handlebars and the hand controls mounted thereon.
In other recumbent tricycle designs, the steering controls are in the form of upright handles located on the sides of the frame and are interconnected to the front or rear steerable wheels through various types of linkage arrangements. While these steering control handles are conveniently located, they are not sophisticated or sufficiently developed enough to enable the rider to also actuate the brake by simply manipulating the same control handle nor do they permit the rider to shift the transmission while holding the control handles. Examples of such control handles are disclosed in the aforementioned U.S. Pat. Nos. 3,913,929, 3,960,392, 4,497,502 and 4,592,563. Another limitation of such control handles is that when used for steering they are tilted or pivoted only in the fore-and-aft direction which can lead to confusion as to the particular direction the handles are to be shifted when attempting to steer in a desired direction.